Growth hormone enhances thymic function in HIV-1–infected adults
Laura A. Napolitano, … , Peter Bacchetti, Joseph M. McCune
Laura A. Napolitano, … , Peter Bacchetti, Joseph M. McCune
Published February 21, 2008
Citation Information: J Clin Invest. 2008;118(3):1085-1098. https://doi.org/10.1172/JCI32830.
View: Text | PDF
Research Article

Growth hormone enhances thymic function in HIV-1–infected adults

Abstract

Growth hormone (GH) is an underappreciated but important regulator of T cell development that can reverse age-related declines in thymopoiesis in rodents. Here, we report findings of a prospective randomized study examining the effects of GH on the immune system of HIV-1–infected adults. GH treatment was associated with increased thymic mass. In addition, GH treatment enhanced thymic output, as measured by both the frequency of T cell receptor rearrangement excision circles in circulating T cells and the numbers of circulating naive and total CD4+ T cells. These findings provide compelling evidence that GH induces de novo T cell production and may, accordingly, facilitate CD4+ T cell recovery in HIV-1–infected adults. Further, these randomized, prospective data have shown that thymic involution can be pharmacologically reversed in humans, suggesting that immune-based therapies could be used to enhance thymopoiesis in immunodeficient individuals.

Authors

Laura A. Napolitano, Diane Schmidt, Michael B. Gotway, Niloufar Ameli, Erin L. Filbert, Myra M. Ng, Julie L. Clor, Lorrie Epling, Elizabeth Sinclair, Paul D. Baum, Kai Li, Marisela Lua Killian, Peter Bacchetti, Joseph M. McCune

×

Figure 2

GH treatment is associated with the emergence of dense thymus tissue in HIV-1–infected adults.

Options: View larger image (or click on image) Download as PowerPoint
GH treatment is associated with the emergence of dense thymus tissue in ...
Representative scans are shown for 9 study participants (numbered 1–9). (A) Cross-sectional comparison of thymus scans from 3 control arm participants (1–3, left panel, no GH) and 3 GH arm participants (4–6, right panel, GH) during the first 6 months of the study. All baseline scans showed low attenuation grayish black adipose tissue in the anterior mediastinum (arrows), consistent with thymic involution. Repeat CT scans obtained 6 months after the baseline scans revealed a marked increase in thymic density in GH recipients (far-right column). This brighter higher-attenuation tissue is consistent with cellular thymus. In contrast, no changes were observed in the absence of GH (second column from left). (B) Longitudinal display of serial thymus CT scans from 3 control arm participants (nos. 7–9) taken at study baseline; 6 months into the study in the absence of GH; pre-GH baseline 12 months into the study; and 18 months into the study after 6 months of GH treatment. As seen in the cross-sectional comparisons, thymus is involuted in the absence of GH, and GH treatment (far-right column) is associated with the emergence of dense thymus tissue.